Weft selector for shuttleless weaving machine

ABSTRACT

A shuttleless web weaving machine, for weaving a web with at least two different weft threads, comprises fork-shaped weft thread input feeder, and a weft thread positioner provided with a displaceable thread guide member and a movable presser foot to position a selected weft thread in front of the weft thread input feeder. The thread guide member is coupled to a weft thread selector comprising at least one pivotably mounted cam disc, the cam disc having an arcuate profile for contacting a respective follower member of the weft thread selector and being angularly displaceable between each of two discrete operative positions, the arcuate profile having two end portions each to contact the follower member in a respective one of the two operative positions and each being substantially concentric with the axis of angular displacement of the respective cam disc.

United States Patent Muller Sept. 9, 1975 Primary Examiner-Henry S. .laudon Attorney, Agent. or Firm-McGiew and Tuttle [57] ABSTRACT A shuttleless web weaving machine, for weaving a web with at least two different weft threads, comprises fork-shaped weft thread input feeder. and a weft thread positioner provided with a displaceabie thread guide member and a movable presser foot to position a selected weft thread in front of the weft thread input feeder. The thread guide member is coupled to a weft thread selector comprising at least one pivotably mounted cam disc. the cam disc having an arcuate profile for contacting a respective follower member of the weft thread selector and being anguiariy displaceable between each of two discrete operative positions, the arcuate profile having two end portions each to contact the follower member in a respective one of the two operative positions and each being substantially concentric with the axis of angular displacement of the respective cam disc.

1 Claim, 5 Drawing Figures WEFT SELECTOR FOR SHU'I'I'LELESS WEAVING MACHINE BACKGROUND OF THE INVENTION The present invention relates to a shuttleless web weaving machine for weaving a web with at least two different weft threads.

By the use of several differently colored weft threads, it is possible to manufacture fabrics with particularly. effective patterns.

In a known shuttleless weaving machine, a special input feeder means is present for each weft thread. This machine is therefore relatively complicated in its construction and operation and moreover allows only the weaving of webs with a relatively simple pattern.

Furthermore, there are weaving machines with only one input feeder means, in which the feed of the weft threads to the input feeder means takes place either directly through the control pulls of a pattern device or through one or more thread guides actuatable by the strings or another control device. In web weaving machines of that kind, the weft thread to be introduced must be accurately positioned in front of the input feeder means. The known constructions have the disadvantage that inaccuracies of the pattern or control device are transferred in full extent to the thread guide means. Such inaccuracies can be caused perhaps by uneven pulling of the control pulls of the pattern device, perhaps a Jacquard control, or due to the vibration of such control pulls. Such disturbances, which can lead to weaving faults, arise particularly at high weaving speed.

SUMMARY OF THE INVENTION According to the invention there is provided a shuttleless web weaving machine for weaving a web with at least two different weft threads, the machine comprising fork-shaped weft thread input feeder means, and weft thread positioning means provided with a dis placeable thread guide member and a movable presser foot to position a selected weft thread in front of the weft thread input feeder means. The thread guide member is coupled to weft thread selector means comprising at least one pivotably mounted cam disc, the or each cam disc having an arcuate profile for contacting a respective follower member of the weft thread selector means and being angularly displaceable between each of two discrete operative positions, the arcuate profile having two end portions each to contact the follower member in a respective one of the two operative positions and each being substantially concentric with the axis of angular displacement of the respective cam disc.

Preferably, the or each cam disc is coupled to a respective cord operated pull-control mechanism, the or each mechanism being operable to position the respective cam disc in a selected one of its two operative positions.

The number of the possible positions of the thread guide member is determined by the number of the control pulls and cam discs present. When, for example, only one control pull and one cam disc is present, the thread guide can assume two positions. In this case, at most two different weft threads can thus be introduced.

Preferably, the weft thread selector means is provided with two cam discs, of which each is swivelled by a respective control pull. By this arrangement, selectably up to four different weft threads can be positioned and introduced.

When more than four different weft threads are to be introduced, the thread guide member can be correspondingly enlarged. For example, up to eight different weft threads can be positioned by weft thread selector means provided with three cam discs.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be more particularly described with reference to the accompanying drawings, in which:

FIG. 1 shows a representation in principle of a weft thread selector and positioning device with two cam discs for the selected introduction of four weft threads;

FIG. 2 shows a schematic representation of the possible positions of the cam disc follower means;

FIG. 3 shows a schematic view of the warp and the thread guide devices at the start of a weft input;

FIG. 4 shows a representation in principle of a weft thread selector and positioning device with three cam discs for the selectable introduction of eight weft threads; and

FIG. 5 shows a schematic representation of the possible positions of a transfer lever of the device represented in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. I shows a thread positioning device with weft thread selector means and a thread guide 9 for the selectable introduction of a maximum of four weft threads. The control ensues through a Jacquard control by means of two control pulls l, by which the two cam discs 3 can be swivelled about the axes 2. The cam discs are sensed by the roller follower members 4a carried on a sensing member 4 of the follower means. In the surroundings of the locations, which are sensed in the two end positions of the control pulls, the cams 3a of each cam disc 3 each have arcuately shaped section 3b and 3c, concentric to the axis 2. The two sections 3b and 3c have different radii and are connected with one another by a continuously extending curve.

With this shape of curve, it is attained that small swivellings of the cam discs do not influence the position of the sensing member 4. Particularly also the influences of vibrations of the control pulls and overshoots, which can arise due to inertia in rapidly operating machines, are thereby eliminated.

The sensing member 4 is connected through the pivot pin 4b and the connecting member 20 with the transfer lever 5 swivellable about the bearing 5a. The motion of the sensing member 4 is transferred by this articulated connection to the transfer lever 5. The connecting member 20 here serves for the guidance of the sensing member 4. It is so constructed and arranged, that the pivot pin 4b executes an up and down movement on swivelling of the cam discs 3.

FIG. 2 shows the possible positions of the sensing member 4, wherein the position changes have been drawn to an exaggerated scale to obtain an easily viewable representation.

When none of the control pulls l is pulled, the sensing member 4 is in the lowermost position and the pivot pin 4b in the position 4-1. On swivelling of the cam disc further removed from the pivot pin 4b, the sensing member 4 is displaced into position 4-2, while on swivelling of the other cam disc the sensing member 4 is displaced into the position 4-3 and on swivelling both cam discs, the sensing member 4 is displaced into the position 4-4. The pivot pin 4b is so arranged on the sensing member 4, that the positions 4-1 to 4-4 become equidistant. The control movement is transferred from the transfer lever 5 through the rope 6 to the lever 7. The rope 6 is attached at an element 70 displaceable along the lever 7. The lever 7 is connected to be secure against rotation with respect to the thread guide 9 provided with four thread eyelets 9a. The rotational axis 8 of the lever 7 and the guide 9 is constructed as a torsion rod and generates the necessary restoring force. The adjustment of the rest position of the thread guide 9 ensues by variation of the length of the rope 6 and the adjustment of the deflecting stroke by displacement of the element 7a.

FIG. 3 shows a schematic view of the warp, the input feeder means 12, the thread guide 9 and a downward presser foot 13 at the start of a weft input. The woven web 14 is guided through the web holders 15. Before the introduction of a weft, the warp threads 1 l are separated, so that a weaving compartment forms itself and the downward presser foot 13, which is swivellable about the axis 17 and driven by an eccentric disc 16, seizes the weft threads by its tip 13a constructed to be fork-like and tensions them downwardly. Corresponding to the position of the thread guide 9 provided with four eyelets 90, one of the weft threads is now so guided that it cuts the axis of the fork-shaped input feeder means 12 and can be seized by this. The input feeder means 12 is so constructed, that loose warp threads can be turned away during the introduction. During the introduction, the input feeder means 12 draws the weft thread to be introduced off the fork-like tip 13a of the downward presser foot 13 now again moving upwardly. When the input feeder means 12 has reached the edge of the weaving compartment lying opposite to the thread guide 9, the loop formed by the introduced weft thread is bound by suitable means. During the completion of the binding process, the input feeder is withdrawn into the initial position, with which the cycle is completed.

FIG. 4 shows follower means provided with three cam discs and one thread guide member with eight thread eyelets. in this construction the bearing 5a is no longer stationary as in the aforedescribed example, but constructed as a feeler roller. by which the cam 30' of the additional cam disc 3' is scanned. For the remainder, the device is constructed similarly as in the embodiment with two cam discs.

in FIG. 5, the possible positions of the transfer lever 5 are shown, wherein the lever deflections are again represented to an exaggerated scale. The points 5-1, 5-2, 5-3 and 5-4 designate the possible positions of the connecting location 5c. For each of these points, there result always according to the positions of the disc 3 two possible positions of the transfer lever 5, thus in total the eight positions 5-1a, S-lb, 5-2a, 5-2b, 5-3a, S-3b, 5-4a and 5-4b.

I claim:

1. in a shuttleless web weaving machine, for weaving a web with at least two different weft threads, and provided with fork-shaped weft thread input feeder means and with weft thread positioning means including a displaceable thread guide member and a movable presser foot operable to position a selected weft thread in front of the input feeder means, weft thread selector means comprising, in combination, three oscillatably mounted cam discs, each having an arcuate profile, each selectively angularly displaceable about a respective axis between two discrete operative positions; and follower means coupled to said thread guide member and including three follower members each engaged with and operable by a respective cam disc; the arcuate profile of each cam disc having two end portions each engageable with the associated follower member in a respective one of said two discrete operative positions of the cam disc; each said end portion being substantially concentric with the axis of its respective cam disc; said thread guide member having eight weft thread guiding eyelets, whereby a selective one of eight different weft threads is positionable in front of said input feeder means. 

1. In a shuttleless web weaving machine, for weaving a web with at least two different weft threads, and provided with forkshaped weft thread input feeder means and with weft thread positioning means including a displaceable thread guide member and a movable presser foot operable to position a selected weft thread in front of the input feeder means, weft thread selector means comprising, in combination, three oscillatably mounted cam discs, each having an arcuate profile, each selectively angularly displaceable about a respective axis between two discrete operative positions; and follower means coupled to said thread guide member and including three follower members each engaged with and operable by a respective cam disc; the arcuate profile of each cam disc having two end portions each engageable with the associated follower member in a respective one of said two discrete operative positions of the cam disc; each said end portion being substaNtially concentric with the axis of its respective cam disc; said thread guide member having eight weft thread guiding eyelets, whereby a selective one of eight different weft threads is positionable in front of said input feeder means. 